Penile density and globally used chemicals in Canadian and Greenland polar bears Christian Sonne a,n , Markus Dyck b , Frank F. Rigét a , Jens-Erik Beck Jensen c , Lars Hyldstrup c , Robert J. Letcher d , Kim Gustavson a , M. Thomas P. Gilbert e , Rune Dietz a a Aarhus University, Facultyof Science and Technology, Department of Bioscience, Arctic Research Centre (ARC), Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark b Wildlife Management Division, Department of Environment, Government of Nunavut, PO Box 209, Igloolik NU X0A 0L0, Canada c University Hospital of Hvidovre, Kettegaards Allé 30, DK-2650 Hvidovre, Denmark d Ecotoxicology and Wildlife Health Division, Science and Technology Branch, Environment Canada, National Wildlife Research Centre, Department of Chemistry, Carleton University, Ottawa, Canada e Center for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350 Copenhagen K, Denmark article info Article history: Received 20 October 2014 Received in revised form 25 November 2014 Accepted 30 December 2014 Keywords: Bone mineral density Canada Climate oscillations Endocrine disrupting chemicals North East Greenland Risk quotient T-score abstract Industrially produced chemicals have been a major environmental concern across our entire Globe since the onset of rapid industrial development around the early 1900. Many of the substances being used are known to be endocrine disrupting chemicals (EDCs) and are also known to be long-range dispersed and to biomagnify to very high concentrations in the tissues of Arctic apex predators such as polar bears (Ursus maritimus). A major concern relating to EDCs is their effects on vital organ–tissues such as bone and it is possible that EDCs represent a more serious challenge to the species' survival than the more conventionally proposed prey reductions linked to climate change. We therefore analyzed penile bone mineral density (BMD) as a key phenotype for reproductive success in 279 polar bear samples born 1990–2000 representing eight polar bear subpopulations. Since EDC concentrations were not available from the same specimens, we compared BMD with published literature information on EDC con- centrations. Latitudinal and longitudinal BMD and EDC gradients were clearly observed, with Western Hudson bears having the highest BMD and lowest EDCs, and North East Greenland polar bears carrying the lowest BMD and highest EDCs. A BMD vs. polychlorinated biphenyls (PCB) regression analysis showed that BMD decreased as a function of the eight subpopulations' PCB concentrations and this relationship was close to being significant (p ¼0.10, R 2 ¼0.39). Risk quotient (RQ) estimation demon- strated that PCBs could be in a range that may lead to disruption of normal reproduction and devel- opment. It is therefore likely that EDCs directly affect development and bone density in polar bears. Canadian bears had in general the best health and the North East Greenland subpopulation being at the highest risk of having negative health effects. While reductions in BMD is in general unhealthy, reduc- tions in penile BMD could lead to increased risk of species extinction because of mating and subsequent fertilization failure as a result of weak penile bones and risk of fractures. Based on this, future studies should assess how polar bear subpopulations respond upon EDC exposure since information and un- derstanding about their circumpolar reproductive health is vital for future conservation. & 2014 Elsevier Inc. All rights reserved. 1. Introduction Long-range transported substances that are known to be en- docrine disrupting chemicals (EDCs), such as polychlorinated bi- phenyls (PCBs), rate with climate change (global warming) and infectious diseases as the most substantial environmental stres- sors of the Arctic ecosystem. The presence of EDCs in the Arctic marine environment is the result of long-range atmospheric transport, which has been known to occur since the 1940s and Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/envres Environmental Research http://dx.doi.org/10.1016/j.envres.2014.12.026 0013-9351/& 2014 Elsevier Inc. All rights reserved. n Corresponding author. Fax: þ45 87 15 50 15. E-mail addresses: csh@bios.au.dk (C. Sonne), MDyck1@GOV.NU.CA (M. Dyck), ffr@bios.au.dk (F.F. Rigét), jebj@dadlnet.dk (J.-E. Beck Jensen), larshyldstrup@dadlnet.dk (L. Hyldstrup), Robert.Letcher@ec.gc.ca (R.J. Letcher), kig@bios.au.dk (K. Gustavson), tgilbert@snm.ku.dk (M.T.P. Gilbert), rdi@bios.au.dk (R. Dietz). Environmental Research 137 (2015) 287–291